The present invention relates to the field of inkjet printing and, in particular, discloses a surface bend actuator vented ink supply ink jet printer.
Many different types of printing have been invented, a large number of which are presently in use. The known forms of printers have a variety of methods for marking the print media with a relevant marking media. Commonly used forms of printing include offset printing, laser printing and copying devices, dot matrix type impact printers, thermal paper printers, film recorders, thermal wax printers, dye sublimation printers and ink jet printers both of the drop on demand and continuous flow type. Each type of printer has its own advantages and problems when considering cost, speed, quality, reliability, simplicity of construction and operation etc.
In recent years, the field of ink jet printing, wherein each individual pixel of ink is derived from one or more ink nozzles has become increasingly popular primarily due to its inexpensive and versatile nature.
Many different techniques of ink jet printing have been invented. For a survey of the field, reference is made to an article by J Moore, xe2x80x9cNon-Impact Printing: Introduction and Historical Perspectivexe2x80x9d, Output Hard Copy Devices, Editors R Dubeck and S Sherr, pages 207-220 (1988).
Ink Jet printers themselves come in many different types. The utilization of a continuous stream of ink in ink jet printing appears to date back to at least 1929 wherein U.S. Pat. No. 1,941,001 by Hansell discloses a simple form of continuous stream electro-static inkjet printing.
U.S. Pat. 3,596,275 by Sweet also discloses a process of a continuous ink jet printing including the step wherein the ink jet stream is modulated by a high frequency electro-static field so as to cause drop separation. This technique is still utilized by several manufacturers including Elmjet and Scitex (see also U.S. Pat. No. 3,373,437 by Sweet et al).
Piezoelectric ink jet printers are also one form of commonly utilized ink jet printing device. Piezoelectric systems are disclosed by Kyser et. al. in U.S. Pat. No. 3,946,398 (1970) which utilizes a diaphragm mode of operation, by Zolten in U.S. Pat. No. 3,683,212 (1970) which discloses a squeeze mode of operation of a piezoelectric crystal, Stemme in U.S. Pat. No. 3,747,120 (1972) discloses a bend mode of piezoelectric operation, Howkins in U.S. Pat. No. 4,459,601 discloses a piezoelectric push mode actuation of the ink jet stream and Fischbeck in U.S. Pat. No. 4,584,590 which discloses a shear mode type of piezoelectric transducer element.
Recently, thermal ink jet printing has become an extremely popular form of ink jet printing. The ink jet printing techniques include those disclosed by Endo et al in GB 2007162 (1979) and Vaught et al in U.S. Pat. No. 4,490,728. Both the aforementioned references disclosed ink jet printing techniques which rely upon the activation of an electrothermal actuator which results in the creation of a bubble in a constricted space, such as a nozzle, which thereby causes the ejection of ink from an aperture connected to the confined space onto a relevant print media. Printing devices utilizing the electro-thermal actuator are manufactured by manufacturers such as Canon and Hewlett Packard.
As can be seen from the foregoing, many different types of printing technologies are available. Ideally, a printing technology should have a number of desirable attributes. These include inexpensive construction and operation, high speed operation, safe and continuous long term operation etc. Each technology may have its own advantages and disadvantages in the areas of cost, speed, quality, reliability, power usage, simplicity of construction operation, durability and consumables.
There is disclosed herein an ink jet nozzle assembly including a nozzle chamber containing ink to be ejected and a fluidic seal comprising a meniscus formed by said ink across two solid surfaces of said assembly that move relative to one another when the assembly is activated in use.
There is further disclosed herein an ink jet nozzle assembly including:
a nozzle chamber having an inlet in fluid communication with an ink reservoir and a nozzle through which ink from said chamber can be ejected;
the chamber including a fixed portion and a movable portion configured for relative movement in an ejection phase and alternate relative movement in a refill phase;
the movable portion being formed in a first wall of said nozzle chamber and having one end traversing adjacent a second wall of said nozzle chamber, said second wall being substantially perpendicular to said first wall; and
the inlet being positioned and dimensioned relative to the nozzle such that ink is ejected preferentially from the chamber through the nozzle in droplet form during the ejection phase, and ink is alternately drawn preferentially into the chamber from the reservoir through the inlet during the refill phase.
Preferably the movable portion includes the nozzle and the fixed portion is mounted on a substrate.
Preferably the fixed portion includes the nozzle mounted on a substrate and a movable portion includes an ejection paddle.
Preferably one end of said first wall further includes a flange including a surface adjacent said second wall.
Preferably said flange is spaced from said second wall by a slot.
Preferably said second wall of said chamber forms one wall of said inlet.
Preferably said movable portion includes a thermal bend actuator.
Preferably the assembly is formed on a silicon wafer.
Preferably said inlet is formed by back etching a back surface of said silicon wafer.
Preferably said back etching comprises a plasma etching of said back surface.
Preferably said movable portion, in being actuated to be eject a drop of ink, restricts a flow of ink into said chamber via said inlet.
Preferably the assembly further includes a slot around a substantial portion of said movable portion, said slot interconnecting said nozzle chamber with an external ambient atmosphere, said slot being dimensioned to provide for fluid movement during operation of said movable portion while not allowing for the ejection of fluid therethrough.
Preferably said thermal bend actuator comprises a conductive heater layer between layers of a substantially non-conductive material having a higher coefficient of thermal expansion.
Preferably said conductive heater layer is arranged in a serpentine form so that, upon conductive heating of said conductive heater layer, said conductive heater layer forms a concertina so as to allow for substantially unhindered expansion of said substantially non-conductive material.
Preferably said substantially non-conductive material comprises substantially polytetrafluoroethylene.
Preferably said silicon wafer is initially processed utilizing a CMOS processing system so as to form a electrical circuit required to operate said ink jet nozzle assembly on said silicon wafer.